1. Field of the Invention
The invention pertains to the field of weights and measurements. More particularly, the invention pertains to a tongue weight donut scale.
2. Description of Related Art
Trailer hitch systems sold in the United States have labeling that indicates the maximum rated total weight capacity and the maximum tongue weight capacity. These are also the hitch systems legal capacities. Distributor and retailers recommend and supply consumers with devices for measuring these limits, including the tongue weight of a towed vehicle. All such devices presently on the market must be used when the towed vehicle is “unhitched” from the towing vehicle. Their use can be dangerous, very cumbersome, time-consuming, labor-intensive, unstable, and discouraging, especially for someone not mechanically inclined or physically strong. The more steps you have to take in any mechanical procedure or task the more that things can go wrong.
Also, because of the arduous task of having to use present day devices to check trailer tongue weight, many people ignore checking it, heading down the public highways endangering themselves and possibly everyone else they meet on the highway.
Most drivers are not fully aware of how important it is to have the tongue weight imposed on their hitch system in a safe range. There are major negative safety issues associated with improperly applied tongue weights, either too high or too low.
Many states in the United States have laws relating to the lawful towing of a vehicle or trailer on the public highways. Lives are at stake when hauling takes place without knowing the tongue weight is within safe and legal limits. Safety and liability in case of an accident are only two of the very important issues that compel the towing consumer to be aware and know their legal and safe towing tongue weight.
Current devices being used to measure tongue weight include bathroom scales, pump type jacks, and public platform scales.
U.S. Patent Application Publication No. 2006/0290102, entitled “Weight Sensing Trailer Ball” by VanBuskirk and published Dec. 28, 2006, discloses a trailer ball device with an integral sensing mechanism to detect a force exerted on the trailer ball, such as the tongue weight of a trailer. In order to be used, the trailer ball device must be installed as the towing vehicle's custom trailer ball, or in place of a removable trailer ball, on the hitch of a towing vehicle.
Johnston (“Load Master Scale”, in Trailer Life, pp. 56 and 58, October 1995) reviews a measuring device (Sherline Products, Vista, Calif., USA) that may be placed under a trailer tongue to measure the tongue weight of a trailer.
The above-mentioned references are hereby incorporated by reference herein.